Hi all,

new to the board, proud owner of an OB8 wants to say hello and ask a question.

I recently calibrated my OB8 and all went fine. No at the end of the procedure I was taking a look at the 3090 on one of the cards in the output section (U503) and by a dumb move I shorted pins 5 and 6 :-( Consequently after that whole voice card went quite. As I supposed I killed off the chip in the process I replace the 3090 on the output section but no sound anyway.

As U503 is connected to the CEM3360 my suspicion was that it was affected by that short, too. As I had a spare CEM I swapped it. The problem now is that there is only a very, very low output on that card. As the TL082 is last in line I thought it was not working either so I replaced it, too but still the signal is low as before.


I am a bit out of ideas for now as looking at the schematics there is not much left to work on.

The only thing that crossed my mind is that there is a 2n3905 attached to the 3090 and that is connected to the VOL pot so maybe it blew. What is its function in this

Another thing is that now on the upper board the panning is not working anymore. I would suspect that the CEM3360 and the TL082 are to be inspected. As I changed both of them again not sure whats left.
Voices and tuning seem to work fine. (I suppose the U504/TL081 is delivering the signal fromt the voices to the tuning unit )


BTW I have an oscilloscope and the schematics so if anyone could give me an adivce what to look out for I would really appreciate.
Thanks!

JF